A New Control Scheme Based on R-APF for Harmonic Power Sharing in Islanded Microgrids

Harmonic power can be shared by controlling the equivalent harmonic impedance of distributed generation (DG) units in islanded microgrids. This paper firstly reviews several methods for controlling the equivalent harmonic impedance of DGs and adopts the method based on resistive active power filter (R-APF). Then, a droop relationship between the equivalent harmonic impedance of DGs and their remaining power capacities (Z(DG)_S-h_eq-(DG)_(remaining) droop relationship) is put forward. And it is combined with the R-APF based control method to form the control scheme for DGs in islanded microgrids. With this control scheme, harmonic power is shared according to the remaining power capacities of DGs. Unlike many existing control schemes for harmonic power sharing, the control scheme proposed in this paper is insensitive to line impedance variations and does not need communication systems. Finally, the effectiveness of the proposed control scheme is verified by simulation results.